--- a/configure.ac	2016-10-09 00:24:41.507447888 +0200
+++ b/configure.ac	2016-10-09 00:29:22.550927024 +0200
@@ -22,7 +22,9 @@
 VERTEX_ENABLE([UNITY],       [unity],       [Unity],        [disable])
 VERTEX_ENABLE([XFWM],        [xfwm],        [XFWM],         [disable])
 
-VERTEX_GNOME
+AC_ARG_WITH(gnome, AS_HELP_STRING([--with-gnome]),
+            [GNOME_VERSION=$withval], [GNOME_VERSION=3.20])
+AC_SUBST([GNOME_VERSION])
 
 AC_CONFIG_FILES([
     common/Makefile